MINNEAPOLIS  — An 11th person in Hennepin County has died after overdosing on the powerful opioid carfentanil.

The Hennepin County Medical Examiner’s Office says the 63-year-old man from Brooklyn Park died April 26 from a mix of carfentanil and trazadone. Like the other 10 people who have died since January, carfentanil wasn’t known to be a factor in his death until more testing was completed.

Routine drug and alcohol screenings don’t detect the drug, so samples have to be sent to a specialized lab.

The opioid is relatively new to Minnesota and is 10,000 times more potent than morphine and 100 stronger than fentanyl. The drug is used as a tranquilizer for elephants or other large animals.

Authorities haven’t found the drug’s source or determined if any of the deaths are connected.